Error compensation for hybrid-computer solution of linear differential equations

Z-transform technique compensates for digital transport delay and digital-to-analog hold. Method determines best values for compensation constants in multi-step and Taylor series projections. Technique also provides hybrid-calculation error compared to continuous exact solution, plus system stability properties

Laser-heated thruster

The development of computer codes for the thrust chamber of a rocket of which the propellant gas is heated by a CW laser beam was investigated. The following results are presented: (1) simplified models of laser heated thrusters for approximate parametric studies and performance mapping; (3) computer programs for thrust chamber design; and (3) shock tube experiment to measure absorption coefficients. Two thrust chamber design programs are outlined: (1) for seeded hydrogen, with both low temperature and high temperature seeds, which absorbs the laser radiation continuously, starting at the inlet gas temperature; and (2) for hydrogen seeded with cesium, in which a laser supported combustion wave stands near the gas inlet, and heats the gas up to a temperature at which the gas can absorb the laser energy

Investigation to identify paint coatings resistive to microorganism growth

All selected coatings contain nutrients that support microbial growth and survival. Incorporation of microbiocidal agents into coatings more susceptible to attack is recommended for improved inhibition of microorganism growth and for increased protection against deterioration of coatings by microorganisms

Flowering and pollination studies with European plum (Prunus domestica L.) cultivars

One of the most important factors affecting the financial outcome of commercial fruit growing is the success of pollination and fertilization, which in turn are dependent on weather conditions, activity of pollinators and the compatibility and overlap in flowering of the cultivars. Before introducing new cultivars, it is obviously important to know the compatibility and flowering characteristics of the genotypes. In order to find out these attributes of seven new and four established plum cultivars, pollen germination tests, hand pollinations and flowering phenology observations were carried out. ‘Prosser 84’ had 70% pollen germination. ‘Opal’ had just 3%, probably due to aged pollen. ‘Anna Späth’ flowered over a short period (13 days) and ‘1468’ and ‘DCA BO 46’ over long (19 days) periods; the overlap of all cultivars was relatively good. With ‘1468’, ‘Victory’, ‘Anna Späth’ and ‘Prosser 84’ flowering intensity varied between years, ‘Jubileum’, ‘V70032’, ‘Tita’ and ‘DCA BO 46’ flowered regularly, the others were intermediate. ‘1468’ and ‘WJ 65’ flowered early, ‘Prosser 84’ and ‘DCA BO 46’ late and the rest fell in between. ‘Victoria’ proved to be self-fertile, ‘Jubileum’, ‘V70032’ and ‘1468’ semi self-fertile. Fruit set percentages after June drop of all crosses were rather low; varying between 0 and 28%. With ‘Tita’, fruit drop occurred approximately two weeks later than with the other cultivar

Investigation of Spacecraft Materials that Support Microorganism Growth

Microorganism growth supporting or biocidal properties of spacecraft paint coating

Laser-heated thruster

The development of a computer program for the design of the thrust chamber for a CW laser heated thruster was examined. Hydrodgen was employed as the propellant gas and high temperature absorber. The laser absorption coefficient of the mixture/laser radiation combination is given in temperature and species densities. Radiative and absorptive properties are given to determine radiation from such gas mixtures. A computer code for calculating the axisymmetric channel flow of a gas mixture in chemical equilibrium, and laser energy absorption and convective and radiative heating is described. It is concluded that: (1) small amounts of cesium seed substantially increase the absorption coefficient of hydrogen; (2) cesium is a strong radiator and contributes greatly to radiation of cesium seeded hydrogen; (3) water vapor is a poor absorber; and (4) for 5.3mcm radiation, both H2O/CO and NO/CO seeded hydrogen mixtures are good absorbers

Analytical study of laser supported combustion waves in hydrogen

A one-dimensional energy equation, with constant pressure and area, was used to model the LSC wave. This equation balances convection, conduction, laser energy absorption, radiation energy loss and radiation energy transport. Solutions of this energy equation were obtained to give profiles of temperature and other properties, as well as the relation between laser intensity and mass flux through the wave. The flow through the LSC wave was then conducted through a variable pressure, variable area streamtube to accelerate it to high speed, with the propulsion application in mind. A numerical method for coupling the LSC wave model to the streamtube flow was developed, and a sample calculation was performed. The result shows that 42% of the laser power has been radiated away by the time the gas reaches the throat. It was concluded that in the radially confined flows of interest for propulsion applications, transverse velocities would be less important than in the unconfined flows where air experiments have been conducted

Investigation of spacecraft materials that support microorganism growth Summary report, 1 Sep. 1968 - 30 Jun. 1970

Investigating spacecraft coatings for resistance to growth of microorganism

Thin-walled pressure vessel Patent

Thin walled pressure test vessel using low-melting alloy-filled joint to attach shell to head